3 replies to this topic

[newtech]

Hello,

A liquid ring vacuum pump, pump discharge the uncondensible such as nitrogen gas and some of its sealant liquid(water) to a separator and the water and nitrogen is exits from a piping from the separator, this piping stretches from the top to the ground level to a tank and this piping is submerged inside the liquid the tank at the ground level which i am told is a barometric seal(location of lrvp and separator is at the top). How does this barometric seal works? the piping from the seperator to the ground level tank should be in vacuum, and the tank is at atmospheric condition,the nitrogen is then vented out to atmosphere. then how does the water and gas flow from the separator to the tank at ground level.I am told that the barometric seal help to prevent any air from entering.how does the liquid and gas flow from vacuum to atmosphere, how do they over come the atmospheric pressure? if they are able to overcome the atmospheric pressure then whats the use of a barometric seal ? is it because of the length of piping from the top to the tank helps to over come atm pressure?

[ankur2061]

newtech,

To understand the fundamentals and design principles of barometric seal have a look at the following links:

http://www.graham-mf...bVacuum/213.PDF

http://www.cheresour...barometric-leg/

Regards,
Ankur.

[Zauberberg]

Water level is provided to ensure positive seal between the process (vacuum) and atmosphere inside the barometric drum - otherwise there would be positive flow from vessel to the process, with possibility of ambient air ingress which can cause hazardous condition.

Flow of water (liquid) from process/vacuum to atmospheric pressure is driven by static head of liquid. Each 10m of water corresponds to 1 bar pressure. For lighter liquids, this height is higher and is calculated through the P = d*g*H formula.

[katmar]

The way you have described this, with the tank on the delivery side of the liquid ring pump, the tank is a pure separator and not a barometric seal.

When placed upstream of the inlet of a liquid ring pump the separator is there to allow liquid to be discharged separately via the barometric leg to the seal tank, while the vapor is drawn into the liquid ring pump (or other vacuum pump) and then discharged to atmosphere. The vapor needs to be pumped to get it to atmospheric pressure, but the liquid (being denser) can discharge itself under gravity via the barometric leg.